Chemokine decoy receptor D6 plays a negative role in human breast cancer

Chemokine binding protein D6 is a promiscuous decoy receptor that can inhibit inflammation in vivo; however, the role it plays in cancer is not well known yet. In this study, we showed for the first time that human breast cancer differentially expressed D6 and the expression could be regulated by some cytokines. More importantly, overexpression of D6 in human breast cancer cells inhibits proliferation and invasion in vitro and tumorigenesis and lung metastasis in vivo. This inhibition is associated with decreased chemokines (e.g., CCL2 and CCL5), vessel density, and tumor-associated macrophage infiltration. Furthermore, D6 expression is inversely correlated to lymph node metastasis as well as clinical stages, but positively correlated to disease-free survival rate in cancer patients. Therefore, D6 plays a negative role in the growth and metastasis of breast cancer.